Heat exchanger for heating of fuel cell combustion air

Abstract

A heat exchanger for a solid-oxide fuel cell assembly. A plurality of parallel tubes conveys fuel cell stack exhaust gas from a first manifold means to a second manifold means. The tubes are highly corrugated to increase the wall area and decrease the wall thickness. The tubes are disposed in a jacket through which is passed incoming air to be heated. The tubes may be linear between two manifolds, or they may be curved such that the first and second manifold functions are accommodated within a single component.

What is claimed is:  
     
         1 . A heat exchanger, comprising: 
 a) at least one corrugated tubular element, having first and second ends, for conveying a first fluid at a first starting temperature; and    b) jacket means surrounding said at least one tubular element for conveying a second fluid at a second starting temperature around said at least one tubular element, whereby heat is transferred between said first fluid and said second fluid.    
     
     
         2 . A heat exchanger in accordance with  claim 1  further comprising first and second connecting means attached to said first and second ends, respectively, for conducting said first fluid into and out of said at least one tubular element.  
     
     
         3 . A heat exchanger in accordance with  claim 1  further comprising at least one turbulator disposed within said at least one tubular element for agitating said first fluid therein.  
     
     
         4 . A heat exchanger in accordance with  claim 1  wherein said at least one corrugated tubular element has a surface area at least twice that of a non-corrugated tubular element of equal length and diameter.  
     
     
         5 . A heat exchanger in accordance with  claim 1  wherein said first fluid and said second fluid are both gases.  
     
     
         6 . A heat exchanger in accordance with  claim 1  wherein said first fluid is fuel cell exhaust and said second fluid is air.  
     
     
         7 . A heat exchanger in accordance with  claim 1  wherein said at least one tubular element is selected from the group consisting of linear, U-shaped, and M-shaped.  
     
     
         8 . A heat exchanger in accordance with  claim 2  further comprising a plurality of said tubular elements arranged for parallel flow of said first fluid therein between said first and second connecting means.  
     
     
         9 . A heat exchanger in accordance with  claim 2  wherein said first and second connecting means include first and second end plates.  
     
     
         10 . A heat exchanger in accordance with  claim 2  wherein said first and second connecting means are comprised in a single end plate.  
     
     
         11 . A heat exchanger in accordance with  claim 8  comprising an array of twenty of said tubular elements arranged into five M-shaped flow paths for said first fluid.  
     
     
         12 . A heat exchanger in accordance with  claim 8  comprising an array of twenty of said tubular elements arranged into ten U-shaped flow paths for said first fluid.  
     
     
         13 . A fuel cell assembly comprising a heat exchanger for exchanging heat between fuel cell exhaust gas and incoming air, said exchanger including 
 at least one corrugated tubular element, having first and second ends, for conveying said exhaust gas at a first starting temperature, and    jacket means surrounding said at least one tubular element for conveying said incoming air at a second starting temperature around said at least one tubular element, whereby heat is transferred between said exhaust gas and said incoming air.